VINTAGE 1938 ZENITH CUBE 6 TUBE SUPERHETERODYNE 3 BAND RADIO 6-S-223. This auction is for a VINTAGE 1938 ZENITH CUBE 6 TUBE SUPERHETERODYNE 3 BAND RADIO 6-S-223! Model #: 6-S-223 ; 6S223 Condition: This item is a vintage collectable. Additional description:. This item does not work. This is the largest of the Zenith "Cube" radios. It has 6 tubes and was made in 1938. It has AM and shortwave bands. This antique radio is an excellent candidate for restoration. None of the wooden knobs are present. The dial glass and bezel are intact. The grill cloth is not present. The case is in EXCELLENT condition with no loose veneer. The finish appears to be original.